As is known, one of the more recent advances in the automotive industry is the development of pneumatic tire sealants to prevent punctures before they occur. In their most usual form, these sealants are viscous fluids, with chunks of raw rubber injected through the tire valve to seal punctures generally up to 1/4 in. diameter. While experience has shown that these tire sealants do, in fact, perform the function for which they are intended, the manner of injecting them through the tire valve leaves much to be desired.
To be more specific, such tire sealants as are commercially available typically are sold in 8 oz. containers, 1 gal. jugs and 5 gal. buckets. Injecting the sealant through the valve entails filling the 8 oz. container with this chunking, viscous fluid, fitting a small length of tubing at one end over a tapered spout at the top of the container, inverting the container and coupling the other end of the tubing over the tire valve, and then squeezing the container to force the fluid through the tubing and into the tire. While, in theory, this procedure should work adequately well, actual usage has shown that it is a hard job to do--squeezing the container too hard shoots the fluid beyond the tire valve and onto the ground, while squeezing the container too easily lengthens the time to discharge fully the container's contents. Although an 8 oz. container may be sufficient to charge a medium size passenger car tire, off-the-road vehicle tires typically require 16 ounces of fluid, while truck tires usually take 36 ounces of this viscous liquid. In these instances, the 8 oz. container has to be filled and refilled from the 1 gal. jug or 5 gal. bucket, as those larger containers cannot readily be squeezed by hand. Not only does such refilling add to the possibility of further liquid spilling on the ground, but actual usage has shown that after 2-3 squeezings of the 8 oz. containers, they tend to lose their shape and resiliency, making it even more difficult to discharge the chunky viscous liquid easily through the tire valve in carrying out the tire charging. Add to this the further tendency of the liquid to itself clog the tire valve in use, the further problem results in even more-and-more spillage and spurting of the sealant under the squeezing force of the container, making the operation all the more messy.
Were this not bad enough, experience has shown the inordinate time spent in effectively carrying out this injection process. That is, even with the skilled user of the tire sealant, it takes approximately 10 minutes to so charge a medium size passenger car tire. To deal, instead, with a commercial truck tire requiring 36 ounces, or so, of this same tire sealant to do a comparable job typically takes more than four times as much effort, commonly taking 45 minutes of manual squeezing--without even considering the added time spent in having to refill the 8 oz. container from the larger jug or bucket size and having to clean up the attendant spillage and mess. Whereas one might accept spending upwards of most one hour to so treat the 4 tires and spare of a medium passenger vehicle, treating just one truck of a commercial fleet having 8-10 tires could take an entire day. This follows not only from the added number of tires to be treated, but from the much larger size of the tires employed. Although not so much of an added burden as a commercial tractor-trailer truck, the situation with off-the-road vehicles or box trucks still reflect the far greater effort required than with medium size passenger cars, because of their accepted need for some 16 ounces of tire sealant fluid to do the job of protecting against blowouts and flat tires.